Mrs Pelosi is the US Speaker of the House of Representatives – second in like to the presidency – and was the most senior US politician to visit Taiwan in 25 years.
She said at the time that China couldn’t “prevent world leaders or anyone from travelling to Taiwan”.
On Thursday, the Chinese embassy in the UK said the MPs’ visit to the “Taiwan region of China” took place despite Beijing’s “firm opposition”.
“This is a flagrant violation of the one-China principle and a gross interference in China’s internal affairs,” a spokesperson said.
The statement added that any moves to undermine China’s interests would be met with “forceful responses”.
Mr Sunak said the closer economic ties of the previous decade had been “naïve” – but added that China’s global significance could not be ignored.
“We recognise China poses a systemic challenge to our values and interests, a challenge that grows more acute as it moves towards even greater authoritarianism,” he said.
The MPs’ visit is one of a number of recent incidents to cause friction in UK-Chinese relations.
The Foreign Affairs Committee – which is separate from the government and made up of politicians from different parties – has held discussions with their Taiwanese counterparts over issues including security.
Taiwan’s Ministry of Foreign Affairs tweeted that Mr Wu held a banquet for the UK delegation and spoke about “increasing authoritarian threats” as well as “worrying issues at home and abroad”.